电网电压不平衡时DFIG网侧变流器新型双环控制策略

New Double-Loop Control Strategy for DFIG Grid-Side Converter Under Unbalanced Grid Voltage

电网电压不平衡时,电网电压出现的负序电压会对双馈风力发电机的正常运行产生很大的影响,甚至损坏发电机组。通过对双馈异步风力发电机网侧变流器的模型进行推导和分析,提出了一种双馈风力发电机网侧变流器在电网不平衡条件下改进的双环控制策略。该策略的外环采用模糊PID控制,而内环采用谐振PR控制,从而通过同时控制正、负序可以消除直流侧二次谐波,得到恒定的直流电压。最后,利用MATLAB/Simulink对该策略进行了试验验证,仿真结果证明了该策略的正确性和有效性。

When the grid voltage unbalance,the grid voltage negative sequence will produce and it will bring great influence on DFIG or even damage the generators. The grid-side converter model doubly fed induction generator was derived and analyzed, a improved control strategy for double-fed wind turbine grid-side converter under unbalanced grid voltage was presented. The control strategy using fuzzy PID for outer loop and resonant control for inner,by simultaneously controlling the positive and negative sequence the second harmonic could be eliminated and finally get a constant DC voltage. Finally,the use of MATLAB / Simulink experimentally validated control strategy and simulation results showed the correctness and effectiveness of the control strategy.